Research On 3D Measurement Technology Based On Radial Space Carrier Phase Shift Method

The fringe projection 3-D profile measurement technology has the advantages of non-contact,high speed and great precision,and it is easy to realize automatic measurement under the control of computer,which has become a widely used in 3-D shape measurement technology.With the rapid development of electronic information industry and the improvement of manufacturing level,the requirements of 3-D shape detection are increasing day by day.The 3-D shape measurement technology is faced with many urgent problems about measurement speed and accuracy.The quality of the phase retrieving directly affects the measurement accuracy,the speed of the fringe projection and the speed of acquisition by CCD affects the imaging speed.Therefore,accurately and efficiently extracting the phase distribution of objects has become a key issue in the research of 3-D shape measurement.Circular fringe has higher sensitivity than straight fringe,and we proposed a radial spatial carrier phase shifting algorithm based on circular fringe.We extracts three new quasi phase shifting fringes with pixel malposition from a captured fringe image in the radial direction by radial digital movement.We get the object information by carrying Fourier transform on these captured distorted fringes,take out the first order,and then make an inverse the Fourier transform.After a simple calculation of the information obtained,the object phase information can be reconstructed conveniently.In addition,the validity of the method is verified by simulations and 3-D measurement of static objects,which improved phase accuracy.The accuracy and instantaneity of this method is proved by the experiment of 3-D shape measurement when the dynamic object moves to different position and the experiment of reconstructing the surface shape of the moving object at different speed.For the 3-D shape measurement demand of small objects,a dynamic 3-D microscopic measurement system based on structural light is proposed in this paper.We take two internal optical paths in the stereo microscope,which are independent of each other and have a certain angle,as the projection light path and the image acquisition light path,respectively.The 3-D shape measurement of small objects will be realized based on the principle of 3-D measurement and the radial spatial carrier phase shifting algorithm.Through the static measurement experiments,we proved the feasibility of the shape measurement of small objects.In the measurement experiment of the dynamic object,we choose to use the marked rotating cone as the measured object,which proves that the 3-D microscopic measurement system has good measurement results about the small dynamic scene.